The evolution of the dielectric constant in various polymers subjected to uniaxial stretch

Dielectric elastomers (DEs) are materials that deform in response to electric excitation, an attractive feature that deems them suitable for various actuation-based devices. The growing interest in these materials leads to many intriguing questions regarding the origin of the electro-mechanical coupling and its relation to the dielectric constant. This work examines the coupled response of four dielectrics: VHB 4910, Polytetrauoroethylene (PTFE), High-density polyethylene (HDPE) and Low-density polyethylene (LDPE). We demonstrate the substantial dependence of their dielectric constants on the deformations. These findings are compared to a recent statistical-mechanics based model which takes into account the structure of the dielectric. A good agreement is found between the theoretical model and the experimental measurements.